I have been on both ends of the dynamics. There was a friend who let me go many years ago and then there was a friend whom I had to let go in recent years. I don't think that the details are relevant here (and only leads to digression), as much as the point that I get that it's painful. However, I've learned and grown from my experience and have moved on. Just as a healthy body heals in time, so does a healthy heart. If your heart is not healthy, you need care, as you are already receiving through therapy.
I don't think that talking to your friend one more time can give you closure. Because what if her answer does not satisfy you? Then you would be left with wondering more and wanting more answers. It could be endless.
By finally ceasing to contact you altogether, she has already given you a closure. She is not going hot and cold; she is not playing the push and pull game; she is not sending you mixed messages.
And even if she was being intentionally untruthful back then, can you change her?
"Help me to accept the things I cannot change." This is part of the serenity prayer.
You can't change the other person or her response, or the lack thereof.
You can only change you. You are already doing the proactive thing by going to therapy. So just keep working on yourself, and God will bless you with a wonderful friendships in the future. You can hope and look forward to that.